Fish&Chip. I used to make up my own salt mixtures for my cichlids. I was very lucky where I used to live, in that the tap water was very soft, so I could adjust hardness easily. Where I currently live the water is much harder. I have two incidents relating to fish-keeping you may like...
1) over several evenings I heard a faint barking/grunting noise while sitting in my living room. I searched for dodgy central heating pipes, blamed the dog, left the room and searched the house: finally I checked the fish tank where the sound had seemed to come from. It was my angel fish. He was making grunts/barks at the female. A few days later there were angel fish eggs all up the chimneys for the aerators... daft fish! I couldn't protect them with netting, so they got eaten by the other fish. Never got any young angel fish, but I was pleased that they were breeding... says my water was good. After that I heard the hapless lovers courting several times. It'd be great if we just had to grunt at a potential partner to get hitched.
2) I discovered that gourami were capable of breathing air courtesy of my cat, Duke. He was a British short-hair. He was damned clever. He could open windows and taught my other cat Maisie how to open microwave ovens to loot the contents. (Cat-burglar comes to mind). Anyway, I returned home from work one night to see the feeding lids on the aquarium open and a gourami flapping around on the sofa! Duke was sitting on the sofa watching it. He'd clearly opened the aquarium, perched on top and hooked out the fish. I think he was waiting for it to die. He didn't seem to like the feel of it on his paws, though he kept tentatively patting it. I've no idea how long it survived out of water. I left at 8:15 am and got back at 5:15pm, roughly. They can last a long time, apparently.
The good news is that I put my Indian gourami back in the tank and it was fine. I also added screws to the feeding flaps and Duke never mastered a screwdriver.